Study Of Secondary Suspension System For High-Speed EMU

With the implementation of One Belt And One Road policy,it has become an important link in the development of modern rail vehicles whether the train is safe,comfortable and stable.The core part of air spring is widely used in high-speed EMU on the secondary suspension system,it has low vibration frequency,adjustable height,with characteristics of transverse damping,good performance,it can effectively improve the operation of EMU in quality,it is an important part of the secondary suspension system.As a result,most domestic high speed passenger cars and subway vehicles are equipped with air springs.An elastic element of air spring as the secondary suspension system,it is very important in the whole system,its stiffness and damping characteristics affect the vibration isolation effect of the air spring system,so the study of its influence on the parameters of the air spring characteristics has very important theoretical significance to design and development of air spring.At present,people usually adopt the following methods to establish the mechanical model of air spring.(1)Using the equation of state of gas and the empirical formula of orifice,the mechanical model of air spring is established and studied.(2)The mechanical model of air spring is established by the finite element method.This method must consider all kinds of nonlinear problems of air spring so as to obtain valuable experimental results.(3)Through a large number of experiments,some theoretical assumptions are adopted,and the accuracy of simulation and the generality of the theoretical formula can not be guaranteed.In this paper,from the angle of the whole car and the characteristics of the air spring,the finite element method is used to study the air spring on the secondary suspension system of EMU.Firstly,the multi-body dynamics model of 250 km/h high speed EMU is built by using SIMPACK software.secondly,the air spring model of finite element analysis is carried out by using SIMPACK,Solidworks and ABAQUS software.Comparing the three air spring mechanics model in the software,a single-degree-free spring mass block model was established,by studying the influence of the change of the parameters of the nonlinear air spring on the dynamic characteristics of the vertical and horizontal dynamic characteristics,and a large number of data and conclusions were obtained.Finally,this mechanical model was applied to the whole vehicle,through calculation,the influence of air spring structure parameters on vertical stability of high-speed EMU is further studied.